Vertical generators for absorption refrigeration units



R. MARTIRI 2,776,548

VERTICAL GENERATORS FOR ABSORPTION REFRIGERATION AUNITS Jan. s, 1957 2 Sheets--Sheel l Filed Jan. 26, 1954 Wav( Lum..

= wlllllllllllll 1 III 1/4 Jan. 8, 1957 R. MARTIRI 2,776,548

VERTICAL GENERATORS FOR ABsoRPTIoN REFRIGERATION UNITS Filed Jan. 26,. 1954 2 sheets-sheet 2 VERTICAL GENERATORS FOR ABSORPTION REFRIGERATION UNITS Roberto Martiri, Buenos Aires, Argentina Application January 26, 1954, Serial No. 466,31'7

1 Claim. (Cl. 62--119.5)

This invention relates to :an improved verticalgenerator for absorption refrigerators of the type comprising sa plurality of fluids circulating under pressure in acl-os'ed system which comprises, as principal elements and apart 4from the generator, a condenser, an evaporator, an a sorber, la col-lector, 'a rectifier, a liquid heat exchanger :and :a -gas heat ex-changer. The iiuids circulating in such systems are an absorbent (for instance water), a refrigerant (for instance ammonia) and an inert gas (for 1nstance hydrogen).

fIn these syst-ems the purpose of the generator is to lseparate the refrigerant from the absorbent for carrying :the former to th-e condenser and to Iraise the weakened liquor to a higher level of the fluid circulation system of the refrigerator which corresponds to fthe weak liquor entrance port of the absorber.

In order to achieve the aforementioned purposes, sever-al generators or boilers have been proposed in the majority of which there is used, in general, a percolator or pump tube which surrounds, in the form of a serpentine the hottest portion of a heater element (rilue for the combustion -gases of a burner or electric heater), so that the strong liquor Iflowing through lthe serpenti-ne is heated to its Iboiling point with the consequent decrease of its :specific Weight, the liquor thus Vascending in the tube till it enters -a container also heated by 'the heat-er element Iand in which the refrigerant is separated completely from the absorbent and is conducted to the condenser in a gaseous state, through a rectifier, while the weak liquor returns to the collector through the absorber.

ln other vertical generators there is used a main generator which is in :communication with .an upper auxiliary generator by means of a vertical percolator tube of reduced cross-section, the lower end of which penetrates into the main generator, the separa-tion of the refrigerant from the absorbent taking place in the upper .generator which is provided with a gas discharge port communicating `with the condenser through a rectier, and 'a weak liquor discharge port communicating with the collector 4through the absorber.

The Ina-in disadvantage of the generators constituted by a serpentine, as mentioned hereinbeforqis that the serpentine deteriorates rather quickly in View of the relatively high temperature of :the fluids circulating therethrough with the consequent formati-on of punctures. Also, lthe serpentine is liable to become obstructed by sediments.

The generators comprising Ia main generator and a vertical pump tube of reduced cross-section, also mentioned herein'before, are free from the disadvantages inherent Ito the serpentine generators but require a irelatively large supply of heat in order to -be able to operate with the requis* e efficiency.

The main object of the present invention consists in eliminating the said 'disadvantages and to provide an eflicient Ivertical genera-tor `of simple layout and capable of operating satisfactorily with a heat source of considerably reduced thermal energy, @by making use, for the United States Patent O l2,776,548 Patented Jari. 8, 1957 ICC 2 elev-ation of the solution of the refrigerant in the gaseous state, which is expelled from the generator boiler :and which is supplied to .an injector enclosed in lan auxiliary chamber to which the strong liquor is bein-g supplied, of a suitable conduit which is provided with a pump or liquid elevator tube forming part of fthe injector.

To achieve the above aims, in the improved ver-tical generator .according to the present invention, for tan .absorption refrigerator .formed of a closed iluid circulation `system enclosing an absorbent, la refrigerant :and an inert gas under pressure land comprising :a Icondenser, an evaporator, an absorber, a collector, a rectiiier, la liquid heat exchanger` and a Igas heat exchanger, and which is constituted of ya :substantially vertical heater element, a cylindrical Iboiler mounted in thermal contact with said heater, a first t-ube which, surrounded by a jacket, constitutes said liquid hea-t exchanger and communicates the liquor disch-arge port of :the boiler with the absorber, a second tube communicating the liquor entrance por-t of the boiler with the entrance port of the condenser, and a third tube communicating the str-ong liquor disch-arge port of the jacket with the strong liquor entrance port of a liquid elevator, the liquid elevator is constituted by an auxiliary chamber which, mount-ed adj-acently .to the lower end of the vertical boiler, is provided `with 1a strong lliquor entrance port, a gas entrance port `in communication with Ithe sole gas discharge port of the boiler through ya fourth tube the extreme of which, corresponding to said gas entrance port of the auxiliary chamber, penetrates into the auxiliary chamber in order to enter i-n the form of .an ejector, into :the entrance end of la pump or elevator tube constituting the sole discharge port of the auxiliary chamber and discharging into said second tube at a point located above the weak liquor level of the closed circualti-on syst-em of the refrigerator.

Other objects and advantages of the present invention Will become .apparent as `the speciiication proceeds.

IThe invention will now be more specifically described with reference to the accompanying `drawings which are to lbe understood as explicative of the invention and not limitative of its scope.

lFig. l is a schematic View in elevation of Ia preferred embodiment of the vert-ical generator according to the present invention.

Fig. 2 is an enlarged view of the injector used in the vertical generator of Fig. l.

Fig. 3 is :a longitudinal section .of `a modified auxiliary chamber which can be used in 'a vertical generator according to the present invention.

Fig. 3a is a cross-section along line rIltI-lilil of lthe auxihary chamber .shown .in Fig. 3.

lfig. 4 is a Aschematic view in elevation of a fur-ther embodiment of the improved vertical generator according to the present invention, and

lFig. 5 is a cross-section along line V-V of Fig. 4. The same reference characters indicate like or corresponding parts or elements throughout .the drawings.

As can tbe observed in Fig. l, the generator according to lthe present invention comprises a vertical heater element formed, :in the present embodiment of the invention, by a flue for the combustion gases of a *burner 2 which is supplied with gas or any other adequate fuel and which can also be :constituted by an electric heater element.

Heater element l i-s mounted in intimate 'thermal contact with a cylindrical boiler 3 forming part of :an absorption refrigerator formed of :a closed circulation system of an .absorbent (for instance water), `a refrigerant (for instance ammonia) and :an inert gas (for instance hydrogen) of known type, which comprises furthermore a condenser, an evaporator, an absorber, a collector, a rectifier, and a gas heat exchanger of known construction which are not shown in the drawings and a liquid heat exchanger a shown partially in Fig. 1.

Boiler i3 is provided with a :discharge port 4 for the strong liquor to which is connected a first tube 5 constituting the inner conduit of the liquid heat exchanger a which comprises `als-o a jacket 6 provided with a gas discharge tube 7 which can be connected to the entrance port of the condenser or lto any other element of the closed circulation system which is i-n communication with the entrance port of the condenser.

In its substantially central part, boiler 3 comprises a liquor entrance port 11 which is in communication with the entrance port of the condenser (not shown) by means of a tube 12.

Jacket 6 of liquid heat exchanger a is provided with a discharge port 8 for the strong liquor to which is joined a tube 9 discharging into the strong liquor entrance port 10 of a liquid elevator b which, according to the present invention, is constituted by an auxiliary chamber 16 mounted adjacent to the lower end of boiler 3 but without be* ing in direct thermal contact with the same.

As can be seen in Fig. l, auxiliary chamber 16 comprises furthermore a sole gas entrance port 15 to which there is joined the discharge end of a tube 14 which is connected at its other end to the sole gas discharge port 13 which is located in the upper part of boiler 3. Tube 14 enters into auxiliary chamber 16 by means of an extension 14' and its end is pointed at 14" to constitute a nozzle which is surrounded by the funnel-shaped end 17 of a liquid pump tube 17 constituting the sole discharge port 18 of auxiliary chamber 16 and the opposite end of which is joined to tube 12 at a point 19 located above the weak liquor level of the closed circulation system of the refrigerator, indicated by line 20.

The strong liquor level of the closed circulation system is indicated by a line carrying reference numeral 21.

ln View of the fact that nozzle 14 of extension 14 penetrates into funnel-shaped end 17 of liquid pump tube 17, both elements form an injector by means of which the pressure of the gas, which exists in the upper part of boiler 3, is used for elevating the liquid contained in auxiliary chamber 16 to discharge port 19 of tube 17, as will be explained hereinafter.

In order to facilitate and control the injector action of elements 14" and 17', the latter is provided with a plurality of apertures 22 as can be seen more clearly in the enlarged view of Fig. 2. The funnel shaped end of tube 17, as shown in this iigure, is provided with apertures in the form of longitudinal cuts which are uniformly distributed over the circumference of the tube. Tt will be understood however, that these apertures may have other configurations, and for instance may be circular.

Tn order to ensure the correct operation of injector 14"-17 of liquid elevator b it is necessary to maintain a substantially exact centering of ejector 14 with respect to the inner bore of tube 17, it being possible to use for this purpose longitudinal centering fins (not shown) soldered to the exterior wall of nozzle 14, or any other adequate means provided that the same do not hinder the flow of the liquid from auxiliary chamber 16 to pump tube 17.

The operation of the improved vertical generator according yto the present invention and shown in Figs. l and 2 is as follows: Once burner 2 is ignited and supposing that boiler 3 contains the solution till level 20, this solution or liquor starts boiling with the consequent formation of gases which accumulate in the upper part of the boiler.

Auxiliary chamber 16 of liquid elevator b is filled with strong liquor since the same is mounted below strong liquor level 21 and in view of the fact that entrance port thereof is in communication with discharge port 8 of jacket 6 of liquid heat exchanger a through tube 9. Liquid pump tube 17 is filled with strong liquor till level 21 and gas discharge tube 14 also contains liquid in its interior part till the same level.

Tube 12 which communicates weak liquor port 11 with the entrance port of the condenser, is filled with liquid till a level which coincides with the weak liquor level indicated by line 20.

All these liquids are in equilibrium and under a uniform pressure which corresponds to the general pressure of the closed circulation system of the refrigerator, but this equilibrium is destroyed once the pressure of the gas in the upper part of boiler 3, corresponding to discharge port 13, reaches a value capable of displacing the liquid contained in the lower part of tube 14 and in extension 14 of the same, this displacement occurring abruptly and being followed by a jet of gas and liquid surging from nozzle 14" and penetrating into the interior of pump tube 17. This jet carries along, as occurs in an injector, the solution contained in auxiliary chamber 16, ltowards the interior of tube 17 in which the column of liquid, due to the thermal energy supplied by the jet of hot gas emerging from nozzle 14 presents a lower specific gravity and ascends in tube 17 till it enters into tube 12 at 19, where the gases ascend through the upper part of tube 12 to wards the condenser, while the liquid descends through the lower part of tube 12 till it enters again into boiler 3 passing through entrance port 11 of the same, the liquid being again heated to its boiling point with a view of obtaining a maximum weakening of the liquor.

The strong liquor which is expelled from liquid elevator b due to the pulsating action of injector 14"-17 is replenished by fresh strong liquor flowing from jacket 6 of exchanger a.

As already mentioned hereinbefore, funnel-shaped end 17 of pump tube 17 is provided with a plurality of openings 22 which, in the embodiment of the vertical generator shown in Figs. l and Z, are constituted by slots distributed uniformly along the circumference of the widened end 17 of the tube. These openings may have other configurations, for instance circular, and their arrangement and total surface of passage govern the etiiciency of the liquid elevator action of the injector constituting the essential part of lthe liquid elevator b of the generator according to the present invention.

In the embodiment of the vertical generator according to the present invention shown in Fig. l, liquid elevator b is constituted by an auxiliary chamber 16 of circular cross-section in which injector 14-17' is mounted in a substantially concentric manner.

Figs. 3 and 3a illustrate a modified embodiment of a liquid elevator b according to the present invention constituted by an auxiliary chamber 16 of fiattened crosssection (see Fig. 3a) provided in its lower end with an entrance port 10 for the strong liquor which is in communication by means of tube 9 with the strong liquor discharge port of jacket 6 of liquid heat exchanger a of the closed circulation system of the refrigerator, while gas entrance port 15 as well as liquid discharge port 18 of auxiliary chamber b are loca-ted in the upper wall of container 16', so that a considerable portion of gas supply tube 14 is located within chamber 16' and is curved in the form of a U, the discharge end being directed upwards, and being surrounded by the lower end of pump tube 17.

In this case, liquid-elevator b is mounted with one of its wider walls located more closely adjacent to flue 1.

The Vertical generator according to a modified version of the present invention and shown schematically in Figs. 4 and 5 differs from that illustrated in Figs. 1 and 2 solely as regards the arrangement of heater element 1, since the latter passes through boiler 3 with a view of obtaining an improved transfer of heat to the liquid contained in the boiler, and with respect to liquid heat exchanger a which is in the form of a serpentine surrounding not only the lower extreme of liue 1 but also enclosing the space occupied by liquid elevator b, pump tube Ami 17 of which extends upwards and discharges into U- shaped tube 12. Besides, pump tube 17 is provided with a curved portion which is in Contact with ue 1 so that an additional amount of heat energy is supplied to the liquid column contained in tube 17, thus making it possible to adjust the elevation of the liquid in accordance with the peculiarities of the closed circulation system of the refrigerator.

The embodiment of vertical generator shown in Figs. 4 and 5 is particularly advantageous for those absorption refrigerators in which the entire closed circulation system must be mounted within a relatively limited space in the posterior part of the cabinet which, in spite of comprising a refrigerator chamber of large volume, is of reduced external dimensions, since the whole unit formed of boiler 3, flue 1, exchanger a, elevator b and tubes 17, 14 and 12 constitutes a compact aggregate which,` even after having been provided with a jacket of thermally insulating material, possesses relatively reduced external dimensions.

It will be appreciated that modifications of the disclosed embodiments of my invention are possible without departing from the spirit of my invention or the scope of the appended claim.

What 1 claim is:

A vertical generator for an absorption refrigerator comprising a substantially vertical heater element, a boiler mounted in thermal contact with said heater, a liquid elevator including an auxiliary chamber mounted adjacent the lower end of said boiler, a liquid heat exchanger positioned above the bottom of said auxiliary chamber and means to supply strong liquor from said liquid heat exchanger to said auxiliary c hamber, said boiler having a single gas discharge port, a tube connected to said gas discharge port and extending downwardly and terminating within said auxiliary chamber in an upwardly directed duit communicating at its lower end nel being apertured, s tially vertical tube w said auxiliary chamb communicating at a point within said boiler with a con a portion thereof element, said con with said boiler.

References Cited in the tile of this patent UNITED STATES PATENTS Munters Nov. 4, Bertsch Feb. 3, Davenport Apr. l2, Ullstrand a Feb. 27, Ullstrand Sept. 24, Ashby June 8, Ehnbom Dec. 28, Kogel Jan. 1, Edel Dec. 30, Kogel Mar. 23, Hellstrorn Oct. 25,

dly directed funnel mounted 

